Mutations

Russia's Sputnik V shot around 90% effective against Delta variant, developers say Russia's Sputnik V vaccine against COVID-19 is around 90% effective against the highly contagious Delta variant of coronavirus, its developers said on Tuesday. Reuters Staff U.S.

MOSCOW (Reuters) -Russia’s Sputnik V vaccine against COVID-19 is around 90% effective against the highly contagious Delta variant of coronavirus, its developers said on Tuesday.

Mixing different types of Covid vaccines can boost immune response, study finds Some European countries have started offering alternatives to AstraZeneca as a second shot after the vaccine was linked to rare blood clots. NBC News

A mixed schedule of vaccines where a shot of Pfizer's Covid-19 vaccine is given four weeks after an AstraZeneca shot will produce better immune responses than giving another dose of AstraZeneca, an Oxford study said on Monday.

A study finds that the Pfizer and Moderna vaccines could offer protection for years

The vaccines made by Pfizer-BioNTech and Moderna set off a persistent immune reaction in the body that may protect against the coronavirus for years, scientists reported on Monday.

The findings add to growing evidence that most people immunized with the mRNA vaccines may not need boosters, so long as the virus and its variants do not evolve much beyond their current forms — which is not guaranteed. People who recovered from Covid-19 before being vaccinated may not need boosters even if the virus does make a significant transformation.

“It’s a good sign for how durable our immunity is from this vaccine,” said Ali Ellebedy, an immunologist at Washington University in St. Louis who led the study, which was published in the journal Nature.

The study did not consider the vaccine made by Johnson & Johnson, but Dr. Ellebedy said he expected the immune response to be less durable than that produced by mRNA vaccines.